That and having a time of the morning by which you first set the timer. Otherwise you (well, me) can faff around going to the loo and making cups of tea making sure everything is ready before you start.

In a particularly unenthused stage of my degree my bestie and I used to make writing dates. One of us would visit the other and although we were both ok about procrastinating on our own work we wanted the other to do well, so we enforced a strict system of “no it’s not your turn to make tea, stay there and write”. It worked.